Which of the following regarding X-rays is INCORRECT?

D. Have higher wavelength than visible light

A. Can penetrate soft tissues of the body

B. Were discovered by Wilhelm Conrad Roentgen

C. Are a form of electromagnetic radiation

D. Have higher wavelength than visible light

Everyday Science · Physics in Everyday Life · page 4 of 44

Light & Optics MCQs with Answers

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Light & Optics (incl. Lenses) MCQs (31–40)

10 MCQs with answers and a short one-liner. Hide answers to test yourself.

Past paper MCQs in this chapter · See all past papers

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31.
If the separation between the slits is halved and the screen distance is doubled, what will be the new fringe width?
Correct Answer: D. Four times the original
One-liner
The new fringe width will be four times the original because fringe width is directly proportional to screen distance and inversely proportional to slit separation.
32.
We get light inside the room in a day time due to ?
Correct Answer: D. Reflection
One-liner
We get light inside a room during daytime due to reflection of sunlight from surrounding surfaces and objects.
33.
How many types of convex lens are there?
Correct Answer: C. 3
One-liner
There are 3 types of convex lenses: biconvex, plano-convex, and concavo-convex (meniscus).
34.
If the power of a lens is +5 diopters, what is its focal length?
Correct Answer: A. 20 cm
One-liner
The focal length of a lens with power +5 diopters is 20 cm.
35.
Past Paper MCQ
Which material is commonly used to make the thread in optical fibre technology?
Correct Answer: D. Glass
One-liner
Optical fibre threads are commonly made of glass (silica), which transmits light signals through total internal reflection.
36.
Which of the following regarding X-rays is INCORRECT?
Correct Answer: D. Have higher wavelength than visible light
One-liner
X-rays have shorter wavelength (higher frequency and energy) than visible light, not higher wavelength.
37.
Which of the following series of hydrogen falls in the infrared region?
Correct Answer: C. Pfund
One-liner
The Pfund series of hydrogen falls in the infrared region of the electromagnetic spectrum.
38.
Spectrum of light formed by the radiation given off by a substance is called _?
Correct Answer: C. Emission spectrum
One-liner
The spectrum of light formed by the radiation given off by a substance is called the emission spectrum.
39.
When light enters from vacuum to water, which of the following quantities will not change?
Correct Answer: B. Frequency
One-liner
When light enters from vacuum to water, its frequency remains unchanged because frequency depends only on the source of light.
40.
The refractive index of glass is ?
Correct Answer: B. 1.5
One-liner
The refractive index of glass is approximately 1.5.

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Light & Optics MCQs with Answers

Light & Optics (incl. Lenses) MCQs (31–40)

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